1. Field of the Invention
The present invention relates to a wire harness required for dealing with electromagnetic noise.
2. Description of Related Art
In recent years, vehicles are equipped with a plurality of various electronics, sensors, and electronic control units (ECU). An ECU controls the electronics and sensors installed in a vehicle. A variety of measures are taken to prevent electromagnetic noise from interfering with the signal lines interconnecting the ECUs and the various electronics and sensors, and the signal lines interconnecting the ECUs (for example, refer to Japanese Patent Laid-open Publication 2015-038838, FIG. 1, paragraphs 0002, 0008).
Japanese Patent Laid-open Publication 2015-038838 discloses a wire harness equipped with twisted pairs where two electric wires are twisted together in a spiral. The twisted pair is sealed with a retainer made of photo-curable resin so that two electric wires are prevented from being relatively displaced. The arrangement prevents the twist from loosening and prevents the wires from separating, which deteriorates the ability of the wire harness to reduce noise.
Many other methods (Japanese Patent Laid-open Publication H8-196016 FIG. 3, and paragraph 0007, for instance) employ a tube-like composite resin protector around the wire harness containing the signal lines, to protect the signal lines routed inside the vehicle from breakage or damage from defective insulation.
Japanese Patent Laid-open Publication H8-196016 discloses a wire harness protector wherein a resin sheet serves as the substrate for the wire harness. The resin sheet is bent into a three-dimensional shape and is capable of retaining this shape. The rectangular substrate is bent along the entire length at locations parallel to each other lengthwise into three parts separated from each other widthwise. The substrate is then assembled into a four-sided tube shape having a central hollow space for inserting a group of electric wires from the wire harness.
However, combining the kind of wire harness described in Japanese Patent Laid-open Publication 2015-038838 that uses a twisted pair wire, the kind of protector described in Japanese Patent Laid-open Publication H8-196016 requires a process for twisting the wires to generate the twisted pair wire The protector must also be secured to the wire harness with tape, requiring another process for assembling the four-sided tube shape. These processes are labor-intensive and inefficient.